If you thought the “Moonlight”/”La La Land” envelope fiasco was Oscars’ most glaring mistake, think again.

The “In Memoriam” segment of Sunday’s show included a tribute to costume designer and four-time nominee Janet Patterson — but ran a photo of the very-much-still-alive Australian producer Jan Chapman by mistake.

The two women worked together on Jane Campion’s 1994 film “The Piano,” for which they both received Oscar nominations, and Chapman’s image does appear in some photo databases under Patterson’s name.